fix: alternative route of getting latest Gitea version

https://gitea.com/gitea/gitea-mirror no longer exists, instead use https://dl.gitea.com/gitea/version.json. Simplifies logic.

lib/lib.sh

@@ -147,8 +147,7 @@ function download_gitea() {
     if ! test -f $DIR_BINARIES/gitea-$version; then
         mkdir -p $DIR_BINARIES
         if [[ $version =~ ^[0-9]+\.[0-9]+$ ]]; then
-            full_version=$(curl -sS "https://gitea.com/api/v1/repos/gitea/gitea-mirror/tags" | jq -r '.[] | .name | select(startswith("v'$version'"))' | grep -v -e '-rc' | sort --reverse --version-sort | head -1)
-            full_version=${full_version#v}
+            full_version=$(curl -sS "https://dl.gitea.com/gitea/version.json" | jq -r '.latest.version')
         else
             full_version=$version
         fi